Field of the Invention
This invention relates to the production of wax trees and more particularly to the design of wax runners. The invention prevents melting wax from flowing over the edge of the wax runner and assures alignment of the wax patterns being attached to the wax runner with the end points of the wax runner.
The Lost Wax Process is a long established process for casting. In the practice of the Lost Wax Process, a pattern of a part to be cast is molded in wax. When the wax pattern is molded, it is molded in one piece with a wax pattern gate. The wax pattern gate is an addition to the wax pattern for the purpose of attachment to the wax runner. Wax runners are also molded separately. Wax runners can have a variety of shapes but essentially have at least one bar with flat surfaces and frequently but not always with a pour cup at one end. The wax pattern gates are affixed to the wax runner. To do this, both the end of the wax pattern gate and the surface of the wax runner need to be heated to melt wax and create a fusion. Once the wax patterns are affixed to the wax runner, ceramic material is placed on the wax runner with the wax patterns attached. Once the ceramic has hardened, it is heated causing the wax to flow out of the ceramic. The ceramic thus forms a mold into which the molten material, frequently a metal, is poured to produce the desired part.
In recent times, much of the Lost Wax Art has been substantially automated. However, the fusion of wax pattern gates to a wax runner has been traditionally a manual operation performed by heating putty knives on a Bunsen Burner to melt the surface of the wax runner and the end of the pattern gate. In the patent application of Ludwig, et al, entitled Process and Apparatus for the Assembly of Wax Trees, Ser. No. 10/304,840, assigned to the same assignee, an advanced process and apparatus is taught for automating the fusion of wax pattern gates to a wax runner.
Maintaining a wax runner in a perfectly flat position when attaching wax patterns is a most desirable goal, but unfortunately that goal is not readily attainable. As a result, portions of the wax runner are penetrated more deeply by the heated blade than other portions. Excess molten wax is a result of excessive melting. Should the excess melted wax run over the side of the wax runner, the wax runner and the wax patterns attached to it are not useable resulting in lost product. Wax runners, in the new automatic process are held in a runner station which holds the runner at both ends. Since wax is not a structurally strong material, the wax runner frequently is at least slightly warped or bent.
Beside it being advantageous to securely hold the wax runner, it is most advantageous to have a certain relationship between the centerline of the ends of the wax runner and the wax patterns. This provides an accurate reference point not only for the wax pattern but also for the resulting castings. The accuracy of the location of the wax runner is especially important with the automated process for affixing wax patterns to wax runners since the robotic devices provide accuracy in all three directions.
Therefore, it is highly advantageous to provide a wax runner which prevents molten wax from running over the edge of a wax runner. It is also desirable to securely hold the wax runners and to maintain a fixed relationship between the ends of the wax runner and the wax patterns.
Objects
Therefore, the objects of this invention are to provide the following:                a wax runner configured to retain molten wax on the melted surface and prevent wax flow over the edge of the wax runner, and        a wax runner configured to retain each wax runner in a fixed position to assure a constant relationship between the ends of the wax runner and the wax patterns being attached to the wax runner.        
These and other objects of the present invention will become readily apparent upon further review of the following specifications and the accompanying drawings.